Various types of artificial firelogs are known and have been formulated to act as a substitute for natural firewood and are designed for use in fireplaces and other environments where natural wood would otherwise be used. Typically, artificial firelogs are made by mixing flammable particles with a binder matrix to form a mixture and then molding or extruding the mixture into an elongated form that resembles a piece of natural wood. Wood particles and other cellulosic-derived materials are readily available and are therefore often used as the flammable particles. A commonly used type of wood particle is saw dust of selected sizes and of various wood types and can be employed in various particle size distributions. Various types of inexpensive waxes, resins, plant extracts and related petroleum derived products are often used as the binders for the particles in the artificial firelogs.
The binder functions to hold the firelog in a desired shape and aids in the combustion process, since it commonly has provides most of the firelog's fuel value during the combustion of the firelog in a fireplace or other suitable combustion location.
Generally, artificial firelogs are formed by extruding the mixture through a bore extrusion die wherein the particles and binder as well as any other materials incorporated therein are compressed and shaped within the extrusion bore. The extruded product is cut into predetermined lengths that are sized to fit in a home fireplace or other combustion site and provide a predictable burn time of typically 2 to 4 hours. The elongated flammable bodies (also know as artificial firelogs) formed by this process are usually placed in a protective outer wrapper or sheath for sale, although this is optional and depends on the aesthetics of sale and the materials selected to form the artificial firelogs.
These firelogs are typically marketed for sale to residential homeowners for use in a home fireplace to provide heat and to provide an attractive fire that simulates the fire produced by a natural wood fire. In order to provide advantages over a natural wood fire, the artificial firelogs are formulated so that they can burn for a few hours without attending to the fire as would be required when burning natural wood. Also, artificial firelogs generally start much easier, burn cleaner and generate less ash compared to natural wood. In order to make use of the artificial fuel log more attractive than use of natural wood, the firelog usually includes means for rapidly igniting it with a match which is applied to the outer wrapper. Further, since the artificial firelog is in many instances being used for the aesthetic enjoyment of a fire in social settings, any attributes that are similar to a traditional wood fire will enhance the pleasure of the products use and more closely simulate a traditional wood fire.
Various types of coverings or coatings have been suggested for use in fuel articles. These coatings or coverings address the need to provide a low cost means for reducing adherence of the wrapper to the firelog.
U.S. Pat. No. 5,118,539 discloses a firelog grating system and discloses use therewith of artificial firelogs containing hemp, millet and sunflower seeds as additives in the firelog. The patentee states at Column 5, lines 7 et seq. that, "Although the use of a typical fuel log 18 is sufficient to generate the desired effect for flame quality, it has been found that by impregnating such fuel log with a variety of seed 24 such as hemp, millet, and sunflower, those commonly found in birdseed, a popping sound is generated much like that which a burning log makes as the moisture in the log is heated and ignites. This popping sound adds to the atmosphere created to make the use of the present invention less distinguishable from a wood burning fire." Although these seeds may provide some modest sound, the disclosed seeds do not provide an effective sound. Testing of various grades of millet and sunflower seeds have shown they do not pop sufficiently well to provide a popping sound and their sounds are very short-lived. Further, hemp seeds are illegal to possess and, accordingly cannot be used as a firelog additive.